U.S. patent number 8,158,687 [Application Number 11/569,338] was granted by the patent office on 2012-04-17 for oil-in-water emulsion for delivery.
This patent grant is currently assigned to Nestec S.A.. Invention is credited to Liliana De Campo, Otto Glatter, Martin Leser, Martin Michel, Laurent Sagalowicz, Heribert Johann Watzke, Anan Yaghmur.
United States Patent |
8,158,687 |
Yaghmur , et al. |
April 17, 2012 |
Oil-in-water emulsion for delivery
Abstract
The present invention concerns an oil-in-water emulsion wherein
the oil droplets of a diameter in the range of 5 nm to hundreds of
micrometers exhibit a nano-sized structurization with hydrophilic
domains with a diameter size in the range of 0.5 to 200 nm and
being formed by a lipophilic additive.
Inventors: |
Yaghmur; Anan (Graz,
AT), De Campo; Liliana (Act, AU),
Sagalowicz; Laurent (Cully, CH), Leser; Martin
(Bretigny, CH), Glatter; Otto (Graz, AT),
Michel; Martin (Lausanne, CH), Watzke; Heribert
Johann (Lausanne, CH) |
Assignee: |
Nestec S.A. (Vevey,
CH)
|
Family
ID: |
34972840 |
Appl.
No.: |
11/569,338 |
Filed: |
May 18, 2005 |
PCT
Filed: |
May 18, 2005 |
PCT No.: |
PCT/EP2005/005411 |
371(c)(1),(2),(4) Date: |
January 30, 2007 |
PCT
Pub. No.: |
WO2005/110370 |
PCT
Pub. Date: |
November 24, 2005 |
Prior Publication Data
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Document
Identifier |
Publication Date |
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US 20070213234 A1 |
Sep 13, 2007 |
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Foreign Application Priority Data
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May 18, 2004 [EP] |
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04011749 |
Sep 16, 2004 [EP] |
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04022046 |
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Current U.S.
Class: |
516/56;
426/89 |
Current CPC
Class: |
A23D
7/011 (20130101); A23D 7/0053 (20130101) |
Current International
Class: |
C09K
3/00 (20060101); A61K 9/107 (20060101) |
Field of
Search: |
;516/56 ;426/89 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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2004008837 |
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Jan 2004 |
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JP |
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2004-514690 |
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May 2004 |
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JP |
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2009-516724 |
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Apr 2009 |
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JP |
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WO 99/63841 |
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Dec 1999 |
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WO |
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WO 00/59475 |
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Oct 2000 |
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WO |
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0243696 |
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Jun 2002 |
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WO |
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WO 02/076441 |
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Oct 2002 |
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WO |
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WO 03/105607 |
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Dec 2003 |
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WO |
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Other References
Praveen et al. (Effect of anti-inflammatories on Pluronic.RTM.
F127: micellar assembly, gelation and partitioning, available
online Jun. 1, 2004, International Journal of Pharmaceutics 278
(2004) 361-377). cited by examiner .
Monduzzi, M. et al., "A 13-C NMR Study of Aqueous Dispersions of
Reversed Lipid Phases," USAmerican Chemical Society, vol. 16, pp.
7355-7358 (2000). cited by other .
Nakano, M. et al., "Small-Angle X-Ray Scattering and 13-C NMR
Investigation on the Internal Structure of "Cubosomes"," USAmerican
Chemical Society, vol. 17, pp. 3917-3922 (2001). cited by other
.
Gustafsson, J. et al., "Submicron Particles of Reversed Lipid
Phases in Water Stabilized by a Nonionic Amphiphilic Polymer,"
USAmerican Chemical Society, vol. 13, pp. 6964-6971 (1997). cited
by other .
Nakano, M. et al., "Dispersions of Liquid Crystalline Phases of the
Monolein/Oleic Acid/Pluronic F127 System," USAmerican Chemical
Society, vol. 18, pp. 9283-9288 (2002). cited by other .
Drummond, C.J. et al., "Surfactant Self-Assembly Objects as Novel
Drug Delivery Vehicles," Current Opinion in Colloid and Interface
Science, vol. 4, pp. 449-456 (2000). cited by other.
|
Primary Examiner: Choi; Ling
Assistant Examiner: Wang; Chun-Cheng
Attorney, Agent or Firm: K&L Gates LLP
Claims
The invention claimed is:
1. An oil-in-water emulsion comprising oil droplets of a diameter
in the range of 5 nm to hundreds of micrometers, the droplets
having an interior comprising nano-sized self-assembled structures
with hydrophilic domains having a diameter size in the range of 0.5
to 200 nm due to a presence of a lipophilic additive, wherein the
emulsion comprises an oil selected from the group consisting of
mineral oils, hydrocarbons, vegetable oils, waxes, alcohols, fatty
acids, mono-, di-, tri-acylglycerols, essential oils, flavouring
oils, lipophilic vitamins, esters, neutraceuticals, terpins,
terpenes and mixtures thereof; a lipophilic additive having a
resulting Hydrophilic-Lipophilic Balance value lower than about 10;
hydrophilic domains in form of droplets or channels; and an aqueous
continuous phase that comprises at least one of emulsion
stabilizers and emulsifiers.
2. An oil-in-water emulsion comprising oil droplets of a diameter
in the range of 5 nm to hundreds of micrometers, the droplets
having an interior comprising nano-sized self-assembled structures
with hydrophilic domains having a diameter size in the range of 0.5
to 200 nm due to a presence of a lipophilic additive, wherein the
oil droplets have an internal structure selected from the group
consisting of L2 structure and a combination of L2 and oil
structure in the temperature range of 9.degree. C. to 100.degree.
C.
3. An oil-in-water emulsion comprising oil droplets of a diameter
in the range of 5 nm to hundreds of micrometers, the droplets
having an interior comprising nano-sized self-assembled structures
with hydrophilic domains having a diameter size in the range of 0.5
to 200 nm due to a presence of a lipophilic additive, wherein the
oil droplets have an L2 internal structure in the temperature range
of 0.degree. C. to 100.degree. C.
4. An oil-in-water emulsion comprising oil droplets of a diameter
in the range of 5 nm to hundreds of micrometers, the droplets
having an interior comprising nano-sized self-assembled structures
with hydrophilic domains having a diameter size in the range of 0.5
to 200 nm due to a, presence of a lipophilic additive, wherein the
oil droplets have an internal structure selected from the group
consisting of L2 structure, LC structure, and a combination of L2
and LC structures in the temperature range of 0.degree. C. to
100.degree. C.
5. An oil-in-water emulsion comprising oil droplets of a diameter
in the range of 5 nm to hundreds of micrometers, the droplets
having an interior comprising nano-sized self-assembled structures
with hydrophilic domains having a diameter size in the range of 0.5
to 200 nm due to a presence of a lipophilic additive, wherein the
oil droplets have a LC internal structure in the temperature range
of 0.degree. C. to 100.degree. C.
6. An oil-in-water emulsion comprising oil droplets of a diameter
in the range of 5 nm to hundreds of micrometers, the droplets
having an interior comprising nano-sized self-assembled structures
with hydrophilic domains having a diameter size in the range of 0.5
to 200 nm due to a presence of a lipophilic additive, wherein the
oil droplets have an internal structure selected from the group
consisting of L3 structure, a combination of L2 and L3 structure, a
combination of La and L2 structure, and a combination of lamellar
crystalline structure and L2 structure in the temperature range of
0.degree. C. to 100.degree. C.
7. The oil-in-water emulsion according to claim 1 comprising
dispersed oil droplets having a nano-sized self-assembled
structured interior comprising mixtures of lipophilic and
hydrophilic additives.
8. The oil-in-water emulsion according to claim 1, wherein the
hydrophilic domains in form of droplets or channels comprise a
material selected from the group consisting of water, a non-aqueous
polar liquid, and combinations thereof.
Description
FIELD OF INVENTION
The present invention concerns an oil-in-water emulsion in which
the dispersed oil droplets exhibit a self-assembled
nano-structure.
BACKGROUND OF THE INVENTION
Emulsions in Industry
Emulsions are common colloidal systems in many industrial products
such as Food, Cosmetics or Pharmaceutical preparations. They are
made of oil droplets which are dispersed in an aqueous continuous
phase. The dispersed oil droplets are stabilised by surface active
molecules which form an adsorption layer around the oil droplets.
In order to disperse the oil phase into the continuous aqueous
phase, homogenisers are used which enable to produce oil droplets
in various size ranges (having a radius from ca 100 nm up to
several hundreds of micrometers). The formation of the adsorption
layer around the oil droplets during the homogenisation step
renders the oil droplets kinetically stable against coalescence,
flocculation or coagulation. The surface active material used in
oil-in-water based emulsion products can either be low molecular
weight hydrophilic surfactants, such as polysorbates,
lysolecithins, monoglyceride derivatives etc, or polymers, such as
proteins, e.g. gelatin or from milk, soya, or polysaccharides, such
as gum arabic or xanthan or mixtures thereof.
Oil-in-water emulsion based products are ubiquitous in--Food,
Cosmetics or Pharmaceuticals. Prominent oil-in-water emulsion-based
food products are for instance milk, mayonnaise, salad dressings,
or sauces. Prominent oil-in-water emulsion-based products used in
the cosmetical or pharmaceutical Industry are lotions, creams,
milks, pills, tablets etc. The oil droplets in such products are
usually made of, for instance, triglycerides, diglycerides, waxes,
fatty acid esters, fatty acids, alcohols, mineral oils, or
hydrocarbons.
Emulsions are used either as a starting material, intermediate or
final product or as an additive to a final product.
Emulsions for Delivery
One of the uses of emulsions in Industry is to deliver active
compounds, such as, flavours, vitamins, antioxidants,
neutraceuticals, phytochemicals, drugs, etc. Administrating of the
active components requires the use of an appropriate vehicle for
bringing an effective amount of the active component into the
desired place of action. Oil-in-water emulsions are commonly used
delivery systems since they take advantage of the increased
solubility of lipophilic active compounds in the oil. In EP
1116515, as an example of using emulsions for controlling flavour
performance, a hydrophobic active ingredient, such as a flavour
component, is mixed into a matrix via an extruder in form of an
oil-in-water emulsion in order to increase the stability of the
introduced active ingredient during further processing of the
product. In WO 00/59475, as an example for a pharmaceutical
oil-in-water emulsion, a composition and method for improved
delivery of ionizable hydrophobic therapeutic agents is described,
which are mixed together with an ionizing agent, a surfactant and a
triglyceride to form an oil-in-water emulsion. WO 99/63841, as an
example for the use of emulsions in the food area, describes
compositions comprising phytosterol having enhanced solubility and
dispersability in an aqueous phase due to the formation of an
emulsion or a microemulsion.
Furthermore, if the oil droplets in the oil-in-water emulsions are
ultra small, e.g. in the order of several nanometers to about 200
nm diameter, the emulsion is called oil-in-water microernulsion or
nano-emulsion (Evans, D. F.; Wennerstrom, H. (Eds.); `The Colloidal
Domain`, Wiley-VCH, New York, (1999)). These emulsions are clear
and thermodynamically stable and, therefore, are for the man
skilled in the art different from ordinary emulsions the latter
being thermodynamically unstable and generally turbid.
Another type of a delivery system are surfactant mesophase
particles described by Gustafsson et al. (Gustafsson, J.;
Ljusberg-Wahren, H.; Almgren, M.; Larsson, K.; Langmuir (1997), 13,
6964-6971).
DESCRIPTION OF THE INVENTION
As state of the art, dispersed oil droplets in oil-in-water
emulsions are used as vehicles for lipophilic molecules which are
dissolved in the oil droplets. The drawback of this kind of
emulsions as a vehicle system is that they are not able to host
crystallinic (i.e., present in a crystalline form), hydrophilic or
slightly amphiphilic molecules alone or in combination with
lipophilic compounds due to the lack of molecular solubility of the
active agents in the oil phase. Especially difficult is the
delivery of crystallinic or amphiphilic or hydrotrope compounds
because of their tendency to disturb the stabilizing function of
the emulsifiers, and, as a consequence, they can destabilize the
emulsion.
The present invention is based on the finding of novel nano-sized
self-assembled structures in the interior of ordinary oil droplets.
The structures are formed by the addition of a lipophilic additive
(LPA) to the oil droplets. Such structures can solubilize not only
lipophilic components but also in the same time hydrophilic and/or
amphiphilic or hydrotropic or crystallinic components. The
nano-sized self-assembled structures inside the oil droplets mainly
consist of nano-sized and thermodynamically stable hydrophilic
domains, i.e., water droplets, rods or channels. The nano-sized
domains, which are formed spontaneously (thermodynamically driven)
inside the emulsion oil droplets, are stabilized by the LPA. The
hydrophilic part of the LPA molecule is part of the hydrophilic
domain structure. The hydrophilic domains can be of the size of 0.5
to 200 nm of diameter, preferably in the range of 0.5 to 150 nm of
diameter, even more preferably in the range of 0.5 to 100 nm of
diameter, and most preferably in the range of 0.5 to 50 nm.
As used herein, the `hydrophilic domain` consists of the water
domains and the hydrophilic headgroup area of the LPA molecules.
Due to their ultra-small size, they also exhibit a large surface
area which is a suitable location for the solubilization of a
variety of different compounds.
The emulsions of this invention are clearly distinguished from
emulsions commonly known as water-oil-water double emulsions. w/o/w
(water/oil/water) double emulsions are oil-in-water emulsions, in
which the oil droplets contain micron-sized water droplets (Garti,
N.; Bisperink, C.; Curr. Opinion in Colloid & Interface Science
(1998), 3, 657-667). The water droplets inside the dispersed double
emulsion oil droplets are prepared (dispersed) by mechanical energy
input, e.g., homogenisation, and, as a consequence, are
thermodynamically unstable and not self-assembled. The diameter of
the inner water droplets in a w/o/w double emulsion are larger than
300 nm diameter. The emulsions of this invention can easily be
distinguished from ordinary w/o/w double emulsions since the
formation of the nano-sized self-assembled structure inside the oil
droplets of the emulsion of this invention is spontaneous and
thermodynamically driven, and the mean diameter of the water
droplets or channels is below 200 nm.
Thus the invention is directed towards oil droplets which contain a
nano-sized self-assembled structure with hydrophilic domains. The
notion `self-assembly` or `self-organization` refers to the
spontaneous formation of aggregates (associates) or nano-structures
by separate molecules. Molecules in self-assembled structures find
their appropriate location based solely on their structural and
chemical properties due to given intermolecular forces, such as
hydrophobic, hydration or electrostatic forces (Evans, D. F.;
Wennerstrom, H. (Eds.); `The Colloidal Domain`, Wiley-VCH, New
York, (1999)). The result of self-assembly does not depend on the
process itself and corresponds to a state of minimum energy (stable
equilibrium) of the system.
JP 2004 008837 discloses an oil in water emulsion which contains
water-soluble solid particles present in the oil droplets. The
particles are in the size range of 20 nm to 10 .mu.m. The particles
are prepared in a water-in-oil (w/o) emulsion by means of
dehydration (i.e., not a spontaneous process) before the whole
particle/oil (S/O) suspension is dispersed in an aqueous phase
using the porous membrane emulsification process.
WO 02/076441 discloses the use of an alcohol-in-fluorcarbon
microemulsion as a precursor for the preparation of solid
nanoparticles. The nanoparticles have a diameter below 200-300
nanometers. Nanoparticle formation is not spontaneous and triggered
by cooling the precursor microemuslion below about 35.degree. C.,
or by evaporating the alcohol in the precursor microemulsion or by
diluting the microemulsion with a suitable polar solvent.
US 2004/022861 discloses a w/o/w double emulsion, in which the oil
droplets containing an aqueous microscopic water phase containing
protein or another hydrophilic agent. The whole double emulsion is
sprayed into, for instance, liquid nitrogen via a capillary nozzle
for production of protein-loaded microparticles.
All these examples describe the non-spontaneous formation of solid
hydrophilic (nano)particles using w/o microemulsions or w/o or
w/o/w double emulsions and needing an external trigger for the
solidification of the hydrophilic domains inside the oil droplets.
After preparation of the (nano)particles they are largely
unaffected by environmental factors such as temperature, pH, or
external fluid properties. It has to be mentioned that ordinary w/o
microemulsions in which the water droplets are not solidified, i.e.
fluid, are largely affected by such environmental factors.
Numerous scientific research has shown that the type of emulsion
(o/w or w/o) formed by homogenization of the respective Winsor
system (Winsor I (o/w microemulsion plus excess of oil) or Winsor
II (w/o microemulsion plus excess of water)) is the same as that
formed in the microemulsion phase which is in equilibrium of its
excess continuous phase. For instance, emulsification of a w/o
microemulsion plus excess water (Winsor II system) gives at
sufficiently high surfactant concentrations, i.e., larger than the
critical concentration of the surfactant in the oil phase
c.mu.c.sub.oil, a w/o emulsion, the continuous phase of which is
itself a w/o microemulsion (B. P. Binks, Langmuir (1993) 9, 25-28).
This means that when an ordinary w/o microemulsion is diluted with
an aqueous phase the formation of a w/o emulsion is preferred over
the formation of an o/w emulsion. Binks et al. (B. P. Binks,
Langmuir (1993) 9, 25-28) explained this behaviour in terms of the
partitioning of the surfactant between the water and oil phase in
relation to Bancroft's rule (W. D. Bancroft, J. Phys. Chem. (1913)
17, 501): if the surfactant is accumulated in the oil phase, i.e.,
better soluble in the oil than in the aqueous phase, the formed
type of emulsion is always of the w/o and not the o/w-type. In
order to form an o/w emulsion from a w/o microemulsion or a Winsor
II system (w/o microemulsion plus excess water), it is necessary
that the surfactant undergoes a phase inversion, i.e., a change of
its solubility from oil-soluble (formation of the w/o emulsion) to
water-soluble (formation of a o/w emulsion) (P. Izquierdo et al.,
Langmuir (2002) 18, 26-30). Using nonionic surfactants such as
alkylethoxylates, e.g. the C.sub.12EO.sub.4, this can be achieved
by cooling the system from 40-50.degree. C. (PIT temperature) down
to 25.degree. C. This is completely different from the present
invention which correlates the phase behaviour of a lipophilic
additive (LPA; forms a w/o microemulsion at room temperature) to
the formation of an o/w emulsion in which the oil droplets,
containing hydrophilic domains, are stabilized by an ordinary
water-soluble emulsifier. In this case the hydrophilic domains are
fluid and not solid. The w/o microemulsion or the oil containing
the hydrophilic domains can be diluted (dispersed) in an aqueous
phase without undergoing a phase inversion and loosing the
hydrophilic domains inside the dispersed oil droplets and without
the necessity of solidifying the internal hydrophilic domains in
the oil droplets before the dispersion step.
According to the invention, the spontaneous formation of the
nano-sized self-assembled structure inside the oil droplets can be
realised in different ways. One way is to add a lipophilic additive
(LPA), that allows the spontaneous formation of the nano-sized
self-assembled structure, to the oil phase prior to the
homogenisation step. The other way is to add the lipophilic
additive (LPA) to the emulsion product before or after the
homogenisation step. In this case the lipophilic additive will
dissolve into the oil droplets and will lead to the spontaneous
formation of the nano-sized self-assembled structure inside the oil
droplets. As homogeniser, an ordinary industrial or lab-scale
homogeniser, such as a Rannie piston homogeniser, a Kinematica
rotor stator mixer, a colloid mill, a Stephan mixer, a Couette
shear cell or a membrane emulsification device can be taken.
Moreover, ultrasound, steam injection or a kitchen mixer are also
suitable to produce the emulsion described in this invention. The
spontaneous formation of the nano-sized self-assembled structure
inside the oil droplets is independent on the energy intake, used
to make the emulsion, and the sequence of LPA addition. This means
that also Microfluidics technics are suitable to make the emulsion
of this invention.
Another route for making the emulsion of this invention is the use
of hydrotropes or water structure breakers, or spontaneous
emulsification which can be chemically or thermodynamically driven
(Evans, D. F.; Wennerstrom, H. (Eds.); `The Colloidal Domain`,
Wiley-VCH, New York, (1999)).
Another route for making the emulsion of this invention is by
combining the spontaneous formation of the nano-sized
self-assembled structure inside the oil droplets with the
spontaneous formation of the oil droplets, i.e., the entire
emulsion of this invention, by adding diblockcopolymer- or
apoprotein-like biopolymers, such as protein-polysaccharide
conjugates or coacervates or protein-polysaccharide,
protein-protein, or polysaccharide-polysaccharide hybrides or
mixtures of polymers or biopolymers or low molecular weight
surfactants.
Emulsion Formulation
The present invention concerns an oil-in-water emulsion, wherein
the oil droplets (having a diameter in the range of 5 nm to
hundreds of micrometers) exhibit a nano-sized structurisation with
hydrophilic domains being formed by a lipophilic additive (LPA).
The LPA can be added as such or made in situ by chemical,
biochemical, enzymatic or biological means. The amount of oil
droplets present in the emulsion of this invention (oil droplet
volume fraction) is the amount generally used in ordinary
oil-in-water emulsion products.
More precisely, the present invention is directed to oil-in-water
emulsions comprising dispersed oil droplets having a nano-sized
self-assembled structured interior comprising (i) an oil selected
from the group consisting of mineral oils, hydrocarbons, vegetable
oils, waxes, alcohols, fatty acids, mono-, di- or
tri-acylglycerols, essential oils, flavouring oils, lipophilic
vitamins, esters, neutraceuticals, terpins, terpenes and mixtures
thereof, (ii) a lipophilic additive (LPA) or mixtures of lipophilic
and hydrophilic additives, having a resulting HLB value
(Hydrophilic-Lipophilic Balance) lower than about 10, preferably
lower than 8. (iii) hydrophilic domains in form of droplets, rods
or channels comprising of water or a non-aqueous polar liquid, such
as a polyol, and an aqueous continuous phase, which contains
emulsion stabilizers or emulsifiers.
As used herein, a `lipophilic additive` (abbreviated also as `LPA`)
refers to a lipophilic amphiphilic agent which spontaneously forms
stable nano-sized self-assembled structures in a dispersed oil
phase. The lipophilic additive (mixture) is selected from the group
consisting of fatty acids, sorbitan esters, propylene glycol mono-
or diesters, pegylated fatty acids, monoglycerides, derivatives of
monoglycerides, diglycerides, pegylated vegetable oils,
polyoxyethylene sorbitan esters, phospholipids, cephalins, lipids,
sugar esters, sugar ethers, sucrose esters, polyglycerol esters and
mixtures thereof.
According to the first embodiment of the invention the oil-in-water
emulsion exhibits oil droplets having an internal structure taken
from the group consisting of the L.sub.2 structure or a combination
of a L2 and oil structure (microemulsion or isotropic liquid
droplets) in the temperature range of 0.degree. C. to 100.degree.
C.
According to the second embodiment of the invention, the
oil-in-water emulsion exhibits oil droplets having a L2 structure
(microemulsion or isotropic liquid droplets) in the temperature
range of 0.degree. C. to 100.degree. C.
According to a third embodiment of the invention, the oil-in-water
emulsion exhibits oil droplets having an internal structure taken
from the group consisting of the L2 structure (microemulsion or
isotropic liquid droplets) or liquid crystalline (LC) structure
(e.g. reversed micellar cubic, reversed bicontinuous cubic or
reversed hexagonal) and a combination thereof in the temperature
range of 0.degree. C. to 100.degree. C.
According to the fourth embodiment of the invention, the
oil-in-water emulsion exhibits oil droplets having a LC internal
structure in the temperature range of 0.degree. C. to 100.degree.
C.
According to a fifth embodiment of the invention, the oil-in-water
emulsion exhibits oil droplets having an internal structure taken
from the group consisting of the L3 structure, a combination of the
L2 and L3 structure, a combination of the lamellar liquid
crystalline (L.alpha.) and L2 structure, and a combination of the
lamellar crystalline and L2 structure in the temperature range of
0.degree. C. to 100.degree. C.
According to a sixth embodiment of the invention, the oil-in-water
emulsion exhibits oil droplets having an internal structure which
is a combination of the previously described structures in the
temperature range of 0.degree. C. to 100.degree. C.
All above mentioned internal structures can be without doubt
determined by SAXS analysis and by cryo-TEM (Qiu et al.
Biomaterials (2000) 21, 223-234, Seddon. Biochimica et Biophysica
Acta (1990) 1031, 1-69, Delacroix et al. J. Mol. Biol. (1996) 258,
88-103, Gustafsson et al. Langmuir (1997) 13, 6964-6971, Portes. J.
Phys: Condens Matter (1992) 4, 8649-8670) and fast Fourier
Transform (FFT) of cryo-TEM images.
For certain applications, the use of temperatures higher than
100.degree. C. (for example retorting temperature) is also possible
and is covered by the present invention. The lipophilic additive
(LPA) can also be mixed with a hydrophilic additive (having a HLB
larger than 10) up to the amount that the mixture is not exceeding
the overall HLB of the mixture of 10 or preferably 8. The additive
(mixture) can also be made in-situ by chemical, biochemical,
enzymatic or biological means.
The amount of added lipophilic additive is defined as .alpha..
.alpha. is defined as the ratio LPA/(LPA+oil).times.100. .alpha. is
preferably higher than 0.1, more preferably higher than 0.5, even
more preferably higher than 1, even more preferably higher than 3,
even more preferably higher than 10 and most preferably higher than
15. The ratio .alpha.=LPA/(LPA+oil)*100 is preferably lower than
99.9, more preferably lower than 99.5, even more preferably lower
than 99.0, even more preferably lower than 95, even more preferably
lower than 84 and most preferably lower than 70. Any combination of
the lower and upper range is comprised in the scope of the present
invention. .alpha. can be given either in wt-% or mol-%. The lower
and higher limit of .alpha. depends on the properties of the taken
oil and LPA, such as the polarity, the molecular weight, dielectric
constant, etc., or physical characteristics such as the critical
aggregation concentration of the LPA in the oil droplet phase.
The emulsion is stabilized by an emulsifier (also called primary
emulsifier) suitable to stabilize ordinary oil-in-water emulsion
droplets. The emulsion can be aggregated (flocculated) or not
depending on the used emulsifier. The emulsifier is selected from
the group consisting of low molecular weight surfactants having a
HLB>8, gelatin, proteins from e.g. milk or soya, peptides,
protein hydrolisates, block co-polymers, surface active
hydrocolloids such as gum arabic, xanthan gum, diblockcopolymer- or
apoprotein-like biopolymers, such as protein-polysaccaride
conjugates or coacervates, or protein-polysaccharide,
protein-protein, or polysaccharide-polysaccharide hybrids,
conjugates or coacervates or mixtures of polymers and
biopolymers.
The emulsifier can also be mixed with the LPA, or with the oil, or
with the LPA and the oil. This means, that the emulsifier can
partly also be present in the interior of the oil droplet and
affecting the internal nano-sized self-assembled structure.
The ratio .beta.=emulsifier/(LPA+oil+emulsifier).times.100
describes the amount of emulsifier used to stabilize the oil
droplets with respect to the oil plus LPA content. .beta. is
preferably higher than 0.1, more preferably higher than 0.5, more
preferably higher than 1, and more preferably higher than 2.
The ratio .beta.=emulsifier/(LPA+oil+emulsifier).times.100 is
preferably lower than 90, more preferably lower than 75 and even
more preferably lower than 50. Any combination of the lower and
upper range is comprised in the scope of the present invention.
.beta. can be given either in wt-% or mol-%. The lower and higher
limit of .beta. depends on the properties of the taken emulsifier,
oil and LPA.
Various active components can be solubilized in the nano-sized
self-assembled structured interior of the oil droplets. They can be
oil-soluble, oil non-soluble, crystallinic or water soluble
components selected from the group consisting of nutraceuticals,
such as lutein, lutein esters, .beta.-carotene, tocopherol,
tocopherol acetate, tocotrienol, lycopene, Co-Q.sub.10, flax seed
oil, lipoic acid, vitamin B.sub.12, vitamin D, .alpha.- and
.gamma.-polyunsaturated fatty acids, phytosterols, flavonoids,
vitamin A, vitamin C or its derivatives, sugars, food supplements,
functional ingredients, food additives, plant extracts,
medicaments, drugs, pharmacologically active components,
cosmetically active components, peptides, proteins or
carbohydrates, aroma, salts and flavours.
In the oil-in-water emulsion according to the invention, the
lipophilic additive is selected from the group consisting of
myristic acid, oleic acid, lauric acid, stearic acid, palmitic
acid, PEG 1-4 stearate, PEG 2-4 oleate, PEG-4 dilaurate, PEG-4
dioleate, PEG-4 distearate, PEG-6 dioleate, PEG-6 distearate,
PEG-8-dioleate, PEG-3-16 castor oil, PEG 5-10 hydrogenated castor
oil, PEG 6-20 corn oil, PEG 6-20 almond oil, PEG-6 olive oil, PEG-6
peanut oil, PEG-6 palm kernel oil, PEG-6 hydrogenated palm kernel
oil, PEG-4 capric/caprylic triglyceride, mono, di, tri, tetraesters
of vegetable oil and sorbitol, pentaerythrityl di, tetra stearate,
isostearate, oleate, caprylate or caprate, polyglyceryl-3 dioleate,
stearate, or isostearate, polyglyceryl 4-10 pentaoleate,
polyglyceryl 2-4 oleate, stearate, or isostearate, polyglyceryl
4-10 pentaoleate, polyglyceryl-3 dioleate, polyglyceryl-6 dioleate,
polyglyceryl-10 trioleate, polyglyceryl-3 distearate propylene
glycol mono- or diesters of C.sub.6 to C.sub.20 fatty acid,
monoglycerides of C.sub.6 to C.sub.20 fatty acid, lactic acid
derivatives of monoglycerides, lactic acid dericatives of
diglycerides, diacetyl tartaric ester of monoglycerides,
triglycerol monostearate cholesterol, phytosterol, PEG 5-20 soya
sterol, PEG-6 sorbitan tetra, hexasterarate, PEG-6 sorbitan
tetraoleate, sorbitan monolaurate, sorbitan monopalmitate, sorbitan
mono trioleate, sorbitan mono and tristearate, sorbitan
monoisostearate, sorbitan sesquioleate, sorbitan sesquistearate,
PEG-2-5 oleyl ether, POE 2-4 lauryl ether, PEG-2 cetyl ether, PEG-2
stearyl ether, sucrose distearate, sucrose dipalmitate, ethyl
oleate, isopropyl myristate, isopropyl palmitate, ethyl linoleate,
isopropyl linoleate, poloxamers, phospolipids, lecithins,
cephalins, oat lipids and lipophilic amphiphilic lipids from other
plants; and mixtures thereof.
The oil-in-water emulsion according to the invention is normally in
liquid form. According to another embodiment of the invention, the
emulsion is dried and is available in powder form.
The oil-in-water emulsion according to the invention is either a
final product or an additive. The amount of the additive in the
final product is not critical and can be varied.
The emulsion described in this invention is a novel type of
emulsion which we name `ISAMULSION` to describe the specific nature
of the oil droplets containing a structure being Internally
Self-Assembled, and to exclude the emulsion of this invention from
ordinary oil-in-water or w/o/w double emulsions, including nano-
and microemulsions, in which the oil droplets do not have a
nano-sized self-assembled structure with hydrophilic domains. The
ISAMULSION droplets basically consist of oil droplets which have a
nano-sized self-assembled structure with hydrophilic domains. This
structure can be of a lamellar liquid crystalline, or a lamellar
crystalline, or of a reversed nature comprising the L2, the
microemulsion, the isotropic liquid phase, the hexagonal, the
micellar cubic, or the bicontinous cubic phase. The structures in
the oil phase can appear as a single nano-structure or as a mixture
of different nano-structures.
It is, therefore, an object of this invention to provide a new
oil-in-water emulsion formulation which can be used for the
delivery of active and/or functional ingredients in the Food, Pet
Food, Neutraceutical, Functional Food, Nutri-cosmetical,
Cosmetical, Pharmaceutical, Drug Delivery or Agro-chemical
Industry.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 shows the structure found in the interior of the ISAMULSION
oil droplets as a function of .alpha.=100* LPA/(LPA+oil),
FIG. 2 shows a Cryo-TEM micrograph of a typical ISAMULSION,
FIG. 3 shows the small angle X-ray scattering (SAXS) pattern of an
ISAMULSION, of the bulk oil phase (nano-structured by LPA), which
was used for making the ISAMULSION and of the corresponding
ordinary emulsion (without LPA, without nano-structure). a.u. means
arbitrary unit in all the figures.
FIG. 4 shows the small angle X-ray scattering (SAXS) pattern of
ISAMULSIONS containing various amounts of LPA, i.e., .alpha. values
(.alpha.=100*LPA/(LPA+OIL)).
FIG. 5 shows the stability of the internal oil droplet structure
over time investigated by means of small angle X-ray scattering
(SAXS) (the same ISAMULSION as mentioned in FIG. 3 is
investigated). Notice that after 4 months there is no change
observable in the internal structure of the oil droplets forming
the ISAMULSION.
FIG. 6 shows the reversibility of the internal structure of the
ISAMULSION droplets upon heating and cooling, measured by means of
small angle X-ray scattering (SAXS) (Same ISAMULSION as in FIG. 3).
It demonstrates the reversibility of structure formation after
heating and cooling. The SAXS curves obtained during cooling to 58,
39 and 25.degree. C. are superimposed on the SAXS curved obtained
during heating to 58, 39 and 25.degree. C., respectively.
FIG. 7 shows a cryo TEM image of ISAMULSION oil droplets (in the
presence of a LPA, with nano-structure) (a) in comparison to the
corresponding ordinary emulsion droplets (in the absence of a LPA,
without nano-structure) (b). Notice that the internal structure
that is visible inside the ISAMULSION droplets (FIG. 7a) is
invisible in the normal oil droplets (FIG. 7b).
FIG. 8(a) shows the small angle X-ray scattering (SAXS) pattern of
the ISAMULSION (with LPA, with nanostructure) used in FIG. 7 and
(d) of the corresponding ordinary emulsion (without LPA, without
nano-structure) used in FIG. 7. (b) and (c) correspond to
ISAMULSIONS with high oil and low LPA content.
FIG. 9 shows the small angle X-ray scattering (SAXS) of a
dispersion containing only LPA, of a normal emulsion containing oil
(and no LPA), of an ISAMULSION obtained by mixing and homogenising
60% of the LPA dispersion and 40% of the normal emulsion.
FIG. 10 shows the pseudo binary phase diagram of a
saturated-unsaturated monoglyceride mixture in the presence of 20%
water.
FIG. 11 shows a schematic of an Isamulsion oil droplet, which
contains hydrophilic domains. Note that the hydrophilic domains can
be sherical or non-spherical, i.e. rods, disks or channels.
FIG. 12 shows the small angle X-ray scattering (SAXS) patterns of
ISAMULSIONS containing oil droplets that have an inverse micellar
cubic structure (space group fd3m).
FIGS. 13-15 show the small angle X-ray scattering (SAXS) patterns
of ISAMULSIONS made with a mixture of monolinolein (MLO) and
di-glycerol monooleate (DGMO) as the LPA.
FIG. 16 shows the small angle X-ray scattering (SAXS) patterns of
ISAMULSIONS made with a mixture of phospholipids
(phospatidylcholine (PC)) and monolinolein (MLO) as the LPA.
FIG. 17 shows the small angle X-ray scattering (SAXS) patterns of
an ISAMULSION made with a phospatidylcholine (PC) as the LPA and
triolein as the oil phase. The composition of the emulsion was 95
wt % water-1.912 wt % triolein-2.643 wt % phosphatidylcholine (PC)
from soybean, (Epikuron 200 from Lucas Meyer; LPA)-0.375 wt %
Pluronic F127.
FIG. 18 shows the small angle X-ray scattering (SAXS) patterns of
an ISAMULSION made with a phospatidylcholine (PC) as the LPA and
vitamin E as the oil phase. The composition of the emulsion was 95
wt % water-1.912 wt % vitamin E acetate-2.643 wt %
phosphatidylcholine (PC) from soybean, (Epikuron 200 from Lucas
Meyer; LPA)-0.375 wt % Pluronic F127.
FIG. 1 represents the typical sequence of structures found in the
interior of the dispersed oil droplets of the ISAMULSION as a
function of the content of the lipophilic additive in % (%
LPA=.alpha.=100*LPA/(LPA+OIL)) and temperature. L2 denotes a
reversed microemulsion-like structure; LC denotes the existence of
a liquid crystalline phase or a mixture of different liquid
crystalline phases. As FIG. 1 shows, a defined nano-sized
self-assembled structure is formed at a given temperature and a
specific amount of added lipophilic additive (.alpha. value) inside
the oil droplets (for a closer description of the mentioned
structures, see Evans, D. F.; Wennerstrom, H. (Eds.); `The
Colloidal Domain`, Wiley-VCH, New York, (1999)). The amount of
added LPA allows to precisely control the type of self-assembly
structure, amount of water present in the hydrophilic domains, the
amount of internal interface and the size, dimension, of the
self-assembly nano-structure formed inside the ISAMULSION droplets.
Depending on the oil-type and type of lipophilic additive (LPA),
the minimum amount of LPA (.alpha.) needed to initiate the
spontaneous formation of the self-assembled internal droplet
structure is between 0.1 and 15 wt-% on the oil phase.
The internal nano-sized self-assembled structure of the oil
droplets in the emulsion can be detected by means of Cryo
Transmission Electron Microscopy or SAXS.
The cryo TEM image of FIG. 2 was obtained using the standard
technique of Adrian et al (Adrian et al. Nature, (1984) 308,
32-36). A home made guillotine was used for sample freezing. A
droplet of 3 .mu.l sample dispersion was deposited onto a copper
grid covered with a holy carbon film containing holes of about 2
.mu.m in diameter. A filter paper was pressed on the liquid side of
the grid (blotting) for removing excess sample solution.
Immediately after liquid removal, the grid, held by tweezers, was
propelled into liquid ethane. Frozen grids were stored in liquid
nitrogen and transferred into a cryo-holder kept at -180.degree. C.
Sample analysis was performed in a Philips CM12 TEM at a voltage of
80 kV. Low dose procedures were applied to minimise beam damage. In
some cases (FIG. 7, Examples 1, 4 and 5) a home build environmental
chamber similar to the one described by Egelhaaf et al (Egelhaaf et
al, J. Microsc. (2000) 200, 128-139) was used. The temperature
before thinning and vitrifying was set at 25.degree. C. and 100%
humidity was used. The ISAMULSION can be identified by the presence
of small bright features inside the oil droplets. FIGS. 2, 7a are
Cryo-TEM micrographs of typical ISAMULSIONs showing characteristic
distances between the bright features of about 7-8 nm. It should be
noted that such bright features are not observed for standard
non-structured emulsions and there is no contrast inside
non-structured emulsion droplets (FIG. 7b).
The SAXS curves of FIG. 3 were obtained by a standard equipment
(Bergmann et al. J. Appl. Cryst. (2000) 33, 869-875), using a X-ray
generator (Philips, PW 1730/10) operating at 40 kV and 50 mA with a
sealed-tube Cu anode. A Gobel mirror is used to convert the
divergent polychromatic X-ray beam into a focused line-shaped beam
of Cu K.sub..alpha. radiation (.lamda.=0.154 nm). The 2D scattering
pattern is recorded by an imaging-plate detector and integrated to
the one-dimensional scattering function I(q) using SAXSQuant
software (Anton Paar, Graz, Austria), where q is the length of the
scattering vector, defined by q=(4.pi./.lamda.)sin .theta./2,
.lamda. being the wavelength and .theta. the scattering angle. The
broad peaks of scattering profiles were desmeared by fitting these
data with the Generalized Indirect Fourier Transformation method
(Bergmann et al. (2000), 33, 1212-1216). The characteristic
distances are given by d=2.pi./q. FIG. 3 shows the small angle
X-ray scattering patterns of an ISAMULSION (same as investigated in
FIG. 2) together with the corresponding non-dispersed bulk oil
phase (nano-structured by LPA) that it is made from, and the
corresponding ordinary emulsion (without LPA, without
nano-structure). It can be seen that the ISAMULSION shows the same
peak position as the non-dispersed bulk oil phase that it is made
from. The characteristic distance for both is about 7.5 nm. This
characteristic distance is higher than the diameter of the
hydrophilic domain. Therefore the hydrophilic domains have a size
smaller than 7 nm. For the man skilled in the art, this small size
of the hydrophilic domains demonstrates that the internal structure
of the oil droplet is thermodynamically stable. Moreover, for the
corresponding ordinary emulsion, in which no LPA is added (no
nano-structure), no peak is observed. This is an additional prove
of the presence of a nano-sized self-assembled structure inside the
oil droplets of an ISAMULSION. It does not change upon dispersion
in water, indicating that the internal ISAMULSION droplet structure
is in a thermodynamic equilibrium state.
Moreover, no change in the ISAMULSION droplet nano-structure is
observable even after several months of storage of the product (see
FIG. 5), indicating the thermodynamic equilibrium of the internal
nano-sized self-assembly droplet structure. The reversibility of
the internal structure formation in the ISAMULSION droplets upon
heating and cooling (see FIG. 6) is another indication of
thermodynamic equilibrium of the formed internal oil droplet
nano-sized self-assembled structure. FIG. 11 shows a schematic of
an oil droplet which has been nano-structured by addition of a LPA.
The structural definition of a hydrophilic domain is specified in
FIG. 11. Hydrophilic domains include the polar part (head group) of
the LPA (and not the hydrocarbon tail region and the water part).
The minimum diameter of a hydrophilic domain can be about 0.5 nm
which is more or less the cross section of 2 head groups containing
no water molecules. The minimum size of the polar part of a
lipophilic addive or emulsifier is about 0.2 nm. The diameter of a
water molecule is about 0.3 nm.
EXAMPLES
The various embodiments of this invention provide an oil-in-water
emulsion in which the dispersed oil droplets exhibit a nano-sized,
self-assembled structure of hydrophilic domains due to the presence
of a lipophilic additive (LPA). The following examples are
illustrative in nature and are not to be construed as limiting the
invention, the scope of which is defined by the appended
claims.
Example 1
Generic Examples of an ISAMULSION Obtained by Homogenisation
Typically 1-5 wt % of a mineral oil, such as tetradecane, was added
to 95 wt % water containing already 0.375 wt % of the emulsifier
(Tween 80 or Pluronic F127 from BASF). 0.5-4 wt % LPA (glycerol
monolinoleate) was then added to the mixture. The total amount of
lipophilic molecules (mineral oil+LPA) was 4.625 wt %.
Ultrasonication was then carried out for 20 minutes. The ISAMULSION
character of the emulsions was confirmed by cryo-TEM images and
SAXS curves such as the ones of FIG. 2 and FIG. 3-4. FIG. 2, FIG.
3, FIG. 5 and FIG. 6 were obtained from those generic examples with
a composition of 2.4 wt % mineral oil(tetradecan)-2.2 wt %
LPA-0.375 wt % primary emulsifier (pluronic F127)-95 wt % water. In
addition, corresponding bulk samples (non dispersed samples
containing the oil and the LPA but no emulsion stabilizer) were
prepared and analysed. The weight ratio
oil(tetradecan)/LPA(glycerol monolinoleate) was 1.1/1.0. The
mixture oil-LPA-water was heated and mixed with a Vortex until the
sample was homogeneous. After addition of 0, 5, or 10 wt % water to
the oil/LPA mix, the sample was clear indicating that the water was
totally solubilized into the oil/LPA mixture and a w/o
microemulsion was formed. After addition of higher amounts of
water, the sample shows phase separation. It was noted that the
samples containing 15 and 20 wt % water show the same SAXS curves
as the corresponding ISAMULSION sample (2.4 wt % mineral oil-2.2 wt
% LPA-0.375 wt % emulsifier). This demonstrates that ISAMULSION
droplets show the same characteristic distance of 7.5 nm as
observed in the corresponding bulk phases (see FIGS. 2 and 3). FIG.
5 demonstrates that the internal structure of the ISAMULSION is
stable for more than 4 months. FIG. 6 demonstrates that the
ISAMULSION can be heated and cooled down to room temperature,
keeping exactly the same internal structure. This demonstrates that
the internal structure of the ISAMULSION oil droplets are in
thermodynamic equilibrium. Moreover, FIG. 4 shows that ISAMULSIONS
are formed (e.g. a peak in the SAXS curve is observed) already with
relatively low LPA and high oil contents (e.g. 3.9 wt % mineral oil
(tetradecan)-0.725 wt % LPA (glycerol monolinoleate), 0.375 wt %
emulsifier (pluronic F127)-95% water). However an ISAMULSION is not
formed when no LPA is present as shown in FIG. 3 (composition 4.625
wt % oil (tetradecan), 0.375 wt % pluronic F127, 95 wt % water).
Also with higher amounts of LPA (.alpha. values) (Examples of
composition: composition 1: 1.32 wt % tetradecan-3.3 wt % LPA-0.375
wt % Pluronic F127; composition 2: 1.75 wt % tetradecan-2.9 wt %
LPA-0.375 wt % Pluronic F127), an ISAMULSION is formed. The
structure is more ordered than observed with a lower .alpha. value
(LPA content) and shows an inversed micellar cubic arrangement of
the hydrophilic domains, as shown by the SAXS curves (FIG. 12).
Example 2
Generic Examples of an ISAMULSION Obtained by the Hydrotrope
Route
1 wt % emulsifier (Pluronic F127) was solubilized in 89 wt % water
forming the aqueous solution. 2.5 wt % mineral oil (tetradecan) and
2.5 wt % LPA (glycerol monolinoleate) were dissolved in 5 wt %
ethanol forming the lipidic solution. The aqueous solution was
slowly added to the lipidic solution while vortexing. At the end of
the process, the ISAMULSION, i.e., droplets having an interior
nano-sized self-assembled structure has spontaneously formed.
Example 3
An ISAMULSION Containing a Flavouring Oil
2 wt % of an essential oil (R+ limonene) was introduced in 95 wt %
water containing already 0.4 wt % emulsifier (Pluronic F127). 2.6
wt % LPA (glycerol monolinoleate) was added to the mixture.
Ultrasonication was carried out for 20 minutes. A dispersion was
formed. As in the case of example 1, SAXS reveals the ISAMULSION
character of the emulsion. The ISAMULSION is spontaneously formed
during the ultrasonication step. This example demonstrates that
flavouring oils, such as limonene, can be used as the oil phase for
the formation of an ISAMULSION structure.
Example 4
An ISAMULSION Containing a Nutrient
2 wt % oil (d-alpha tocopheryl acetate) was introduced in 84.625 wt
% water containing already 0.375 wt % emulsifier (Pluronic F127)
and 10 wt % maltodextrin. 2.5 wt % LPA (DimodanU/J (about 62%
glycerol monolinoleate, 22% glycerol monooleate, 14% saturated
monoglyceride) Danisco, Danmark) and 0.5% ascorbic acid were added
to the mixture. Ultrasonication was then carried out for 2 minutes.
As in the case of example 1, SAXS reveals the ISAMULSION character
of the emulsion. The nano-sized self-assembled structure inside the
oil droplets is spontaneously formed during the ultrasonication
step. This ISAMULSION can be spray or freeze dried obtaining a free
flowing powder, which can be redispersed into water. This example
demonstrates that nutritional oils, such as vitamin E, can be used
as the oil phase for the formation of an ISAMULSION structure.
Example 5
ISAMULSIONS Using a Triglyceride Oil
ISAMULSIONS can also be formed with other oils, for instance with
diglyceride or triglyceride oils. 0.5-4.5 wt % of soybean oil was
mixed with 0.5-4 wt % LPA (Dimodan U/J, Danisco, Dannmark). This
mixture was added to 95% water containing 0.375% of the emulsifier
(Pluronic F127). The total amount of lipophilic molecules (oil+LPA)
was 4.625 wt %.
The mixture was sheared using a Polytron (Kinematica, Switzerland)
for five minutes.
The ISAMULSION character of the emulsions was confirmed by cryo-TEM
images (FIG. 7a), SAXS (FIG. 8a) and examination of the
corresponding bulk samples (as it was done for example 1). FIGS.
7a-8a were obtained from those generic examples with a composition
of 1.525 wt % triglyceride oil-3.1 wt % LPA-0.375 wt % primary
emulsifier (pluronic F127)-95 wt % water. SAXS shows that
ISAMULSIONS are formed also for lower LPA contents, such as for
2.775 wt % triglyceride oil and 1.85 wt % LPA in the presence of
0.375 wt % primary emulsifier (pluronic F127) and 95 wt % water
(FIG. 8b) and for 3.2375 wt % triglyceride oil-1.3875 wt %
LPA-0.375 wt % primary emulsifier (pluronic F127)-95 wt % water
(FIG. 8c). No internal structure is observed inside ordinary
soybean oil droplets, e.g. in the absence of LPA (FIG. 7b; FIG.
8d).
In FIG. 9, the SAXS curves of 3 different dispersions are given:
(i) of a dispersion containing only LPA and emulsifier (4.625 wt %
LPA-0.375% emulsifier-95% water), (ii) of a normal emulsion
containing oil and no LPA (4.625 wt % oil-0.375% emulsifier-95%
water) and (iii) of a mixture of the dispersion (i) and (ii),
namely 60% of (i) and 40% of (ii). The mixture (iii) was mixed 5
minutes by means of a Polytron. The SAXS curve of the mixture (iii)
(FIG. 9) shows that the internal structure of the mixture is very
different from the LPA dispersion (i) and from the normal emulsion
(ii) (FIG. 8a). This demonstrates that the obtained internal
structure of the ISAMULSION droplets is not dependent on the
sequence of mixing and processing.
Example 6
An ISAMULSION Containing a Mixture of 2 LPA's, Namely a Saturated
and Unsaturated Monoglyceride
0-1.8% mineral oil (tetradecan) was added to 0.2-2% LPA. The LPA
was a mixture of saturated monoglycerides (Dimodan HR, (saturated
monoglycerides containing 90% of glycerol monostearate), Danisco,
Denmark) and unsaturated monoglycerides (Dimodan U/J, Danisco,
Denmark). The total amount of lipophilic molecules (Oil+LPA) was
3%. The mixture was added to 96.7% water containing 0.3% Tween 80
as emulsifier. Ultrasonication was carried out for 2 minutes. As
indicated by the pseudo binary phase diagram of the saturated
monoglyceride (Dimodan HR)-unsaturated monoglyceride (Dimodan U)
mixture obtained at 20% water (FIG. 10), the formation of a stable
L2 phase can be obtained at high temperatures after addition of the
saturated monoglyceride to the unsaturated monoglyceride sample,
indicating that L2 based ISAMULSIONS can be formed at high
temperatures. For example, for the compositions 1% tetradecan-1%
saturated monoglycerides-1% unsaturated monoglycerides-0.3% Tween
80 and 1% tetradecan, ISAMULSIONS are present and stable at
temperatures higher than 60.degree. C.
Example 7
ISAMULSIONS made of a Monoglyceride (MLO) and Diglycerol Monooleate
(DGMO)
Mixtures containing mineral oil (tetradecan), glycerol
monolinoleate and diglycerol monooleate (DGMO) was added to 95.375
wt % water containing already 0.375 wt % emulsifier (Pluronic
F127). Ultrasonication was then carried out for 20 minutes.
SAXS reveal the ISAMULSION character of the mixtures (FIG. 13-15).
Compared to ISAMULSIONS made only with glycerol monooleate and
without DGMO (FIG. 13-15), the SAXS peaks are shifted towards
higher distances, when DGMO is used, demonstrating that the
hydrophilic domains are getting larger and that a higher amount of
water can be solubilized in the droplets in the presence of DGMO.
This example demonstrates that mixtures of different LPA's can be
used to form the characteristic structure of ISAMULSION oil
droplets and that the characteristic hydrophilic domain size can be
tuned by adjusting the used LPA.
Example 8
ISAMULSIONS made of a Monoglyceride and a Phospholipid
Mixtures containing mineral oil (tetradecan), phosphatidilcholine
from soya oil (PC) and monolinolein (MLO) was added to 95.375 wt %
water containing already 0.375 wt % emulsifier (Pluronic F127).
Ultrasonication was then carried out for 20 minutes.
SAXS reveals the ISAMULSION character of the mixtures (FIG. 16).
This example demonstrates that phospholipids can be used to form
the characteristic structure of ISAMULSION oil droplets.
Example 9
Solubilization of Molecules which are only Sparingly Soluble in the
Oil at Room Temperature
A mixture of 1.1 wt % soya oil, 0.3 wt % free phytosterol (ADM,
USA) and 1.7 wt % LPA (Dimodan U) was heated to 130.degree. C. till
the solution was clear. It is then cooled down to 80.degree. C. and
added to a 0.2% Tween 80 solution at 80.degree. C. Ultrasonication
was performed for 2 minutes. The dispersion was cooled down to room
temperature. No lumps and no (or very few) crystals were evidenced
by polarized microscopy. The reference emulsion system (oil
contains no LPA, 2.8 wt % soya oil-0.31 phytosterol-0.2 wt % tween
80) showed lots of phytosterol crystals having a size up to the
millimeter range, as observed under the polarized microscope. This
example demonstrates that crystalline lipophilic ingredients or
nutrients can be solubilized in the interior of the structure of
ISAMULSION oil droplets in their molecular form slowing down or
preventing their recrystallisation.
Example 10
An ISAMULSION Containing Polysaccharides
1.2 wt % Soya oil-1.7% Dimodan U (LPA)-0.0075 wt % Dextran from
Fluka (molecular weight of 1500 D)-0.14 wt % water was first mixed,
heated and homogenized with a vortex till a homogeneous clear
solution was formed. This solution was added to 96.75 wt % water in
which 0.2 wt % Tween 80 was dispersed. The mixture was treated by
ultrasonication for 2 minutes. An ISAMULSION was formed. This
example demonstrates that polymeric molecules can be solubilized in
the ISAMULSION.
Example 11
An ISAMULSION Containing an Amino Acid
0.51 wt % Soya oil-2.49 wt % Dimodan U (LPA)-0.01 wt %
L-Leucine-0.5 wt % water was first mixed, heated and homogenized
with a vortex till forming an homogeneous clear solution. This
solution was added to 96.29 wt % water in which 0.2 wt % Tween 80
was dispersed. The mixture was treated by ultrasonication for 2
minutes. An ISAMULSION was formed.
Example 12
An ISAMULSION Containing a Sugar
0.02 wt % Soya oil-2.98% Dimodan U (LPA)-0.02 wt % xylose-0.35 wt %
water was first mixed, heated and homogenized with a vortex and let
cooled down to room temperature. This solution was added to 96.43
wt % water in which 0.2 wt % Tween 80 was dispersed. The mixture
was treated by ultrasonication for 2 minutes. An ISAMULSION was
formed. This example demonstrates that hydrophilic ingredients can
be solubilized in the ISAMULSION.
Example 13
An ISAMULSION Containing an Antioxidant
0.51 wt % soybean oil-2.49 wt % Dimodan U (LPA)-0.03 wt %
Lyc-O-Mato from Lycored (contains 10% of lycopene) were first
heated and mixed with a vortex till the formation of a homogeneous
solution. The solution was added to 96.77 wt % water in which 0.2
wt % Tween 80 was dissolved. The mixture was treated by
ultrasonication for 2 minutes. An ISAMULSION was formed having the
lycopene solubilized in the interior nanostructure of the oil
droplets. This example demonstrates that lipophilic antioxidants
can be solubilized in the interior of the structure of ISAMULSION
oil droplets giving rise to a homogeneous emulsion.
Example 14
An ISAMULSION Using Phosphatidylcholine (PC) as LPA
0.1912 g of triolein-0.2643 g phosphatidylcholine (PC) from
soybean, (Epikuron 200 from Lucas Meyer; LPA)-were mixed together
with 9.5 g water and 0.0375 g of Pluronic F127 (emulsifier), and
ultrasonicated for 20 minutes. The resulting emulsion had the
features of an ISAMULSION, i.e., droplets having an interior
nano-sized self-assembled structure that has spontaneously formed,
as revealed by SAXS (see FIG. 17). An ISAMULSION is also obtained
if 0.1912 g of vitamin E acetate-0.2643 g phosphatidylcholine (PC)
from soybean, (Epikuron 200 from Lucas Meyer; LPA)-were mixed
together with 9.5 g water and 0.0375 g of Pluronic F127
(emulsifier), and ultrasonicated for 20 minutes (FIG. 18).
Example 15
An ISAMULSION Using Phospholipid Mixtures as LPA and a Mixture of
Different Oils
2.2 wt % egg-yolk soybean phosphatidylcholine (Lucas Meyer) was
mixed with 2.2 wt % diolein and 0.6 wt % tetradecane. This mixture
was added to 94.625 wt % water containing 0.375 wt % of the
emulsifier (Pluronic F127). Ultrasonication was then carried out
for 40 minutes. An emulsion having the typical ISAMULSION features
was formed. The PC can also be mixed with phopshatidylethanolamine
(PE) or another Phospholipid in order to obtain the ISAMULSION
features. Any combination of different phospholipids and oils is
possible to use and generating the typical ISAMULSION features
described in this invention.
Example 16
An ISAMULSION Using Phosphoethanolamine (PE) as LPA and Oil
2.2 wt % 1,2-Dioleoyl-sn-Glycero-3-Phosphoethanolamine (AvantiPolar
Lipids) was mixed with 0.8 wt % soybean oil. This mixture was added
to 96.7 wt % water containing 0.3 wt % of the emulsifier (Pluronic
F127). Ultrasonication was then carried out for 40 minutes. An
emulsion having the typical ISAMULSION features was formed.
In all the described examples, the size of the hydrophilic domains
in the dispersed emulsion droplets is in the range of 0.5 nm to 15
nm.
The ISAMULSIONS prepared according to the above mentioned examples
can be used as such or as an additive.
Having now fully described the invention, it will be understood by
those of ordinary skill in the art that the same can be performed
within a wide and equivalent range of conditions, formulations and
other parameters without affecting the scope of the invention or
any embodiment thereof.
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